Light conversion structure, backlight module, color filter substrate and display device

ABSTRACT

A light conversion structure, and a backlight module, a color filter substrate, and a display device including the light conversion structure are provided. The light conversion structure includes a light filter structure including a first optical film layer and a second optical film layer alternately arranged and attached to each other in a total number of N, N is an even number, one of a surface of the first optical film layer far away from the second optical film layer and a surface of the second optical film layer far away from the first optical film layer is a light incident surface of the light filter structure, and the other one is a light-exiting surface.

The present application claims priority of the Chinese PatentApplication No. 201710959492.0 filed on Oct. 16, 2017, the disclosure ofwhich is incorporated herein by reference in its entirety as part of thepresent application.

TECHNICAL FIELD

At least one embodiment of the present disclosure relates to a lightconversion structure applied to a display device, and a backlightmodule, a color filter substrate and a display device including thelight conversion structure.

BACKGROUND

Currently, more and more displays use a quantum dot color filter insteadof a traditional color filter. Quantum Dot (QD) can also be referred toas nanocrystal, and has a particle size generally in the range of 1-20nm. Because electrons and holes are subjected to quantum confinement,the quantum dot is converted from a continuous energy band structure toa discrete energy level structure with molecular characteristics and canemit light of a color different from that of an excitation light afterbeing excited. The quantum dot can provide large color gamut and goodcolor saturation, which can improve an image quality.

SUMMARY

At least one embodiment of the present disclosure provides a lightconversion structure, and a backlight module, a color filter substrateand a display device including the light conversion structure.

At least one embodiment of the present disclosure provides a lightconversion structure applied to a display device, including: a lightfilter structure including a first optical film layer and a secondoptical film layer which are alternately arranged and attached to eachother, a total number of the first optical film layer and the secondoptical film layer being N, wherein N is an even number, and arefractive index of the first optical film layer is greater than that ofthe second optical film layer, one of a surface of the first opticalfilm layer far away from the second optical film layer and a surface ofthe second optical film layer far away from the first optical film layeris a light incident surface of the light filter structure, and the otherone of the surface of the first optical film layer far away from thesecond optical film layer and the surface of the second optical filmlayer far away from the first optical film layer is a light-exitingsurface of the light filter structure; a part of incident light of firstcolor that is reflected by the light incident surface is a firstreflected light, a part of the incident light of first color that isreflected by an interface between the first optical film layer and thesecond optical film layer is a second reflected light, and an opticalpath difference between the first reflected light and the secondreflected light is an integer multiple of a wavelength of the incidentlight of first color.

For example, a part of the incident light of first color that isreflected by a side of the light-exiting surface facing the interface isa third reflected light, and an optical path difference between thefirst reflected light and the third reflected light is an integermultiple of the wavelength of the incident light of first color.

For example, the light filter structure includes one pair of firstoptical film layer and second optical film layer, the light incidentsurface is a surface of the second optical film layer far away from thefirst optical film layer, the first optical film layer has a refractiveindex of n1 and a thickness of d1, and the second optical film layer hasa refractive index of n2 and a thickness of d2, the incident light offirst color has a wavelength of λ, and the incident light of first colorsatisfies the following formulas upon being incident into the lightfilter structure:

2n ₂ d ₂=2k*(λ/2),k=1,2,3 . . . ;

2n ₂ d ₂+2n ₁ d ₁−(λ/2)=2k′*(λ/2),k′=1,2,3 . . . ;

4n ₂ d ₂=2k″*(λ/2),k″=1,2,3 . . . .

For example, the light filter structure includes one pair of firstoptical film layer and second optical film layer, the light incidentsurface is a surface of the first optical film layer far away from thesecond optical film layer, the first optical film layer has a refractiveindex of n₁ and a thickness of d₁, and the second optical film layer hasa refractive index of n₂ and a thickness of d₂, the incident light offirst color has a wavelength of λ, and the incident light of first colorsatisfies the following formulas upon being incident into the lightfilter structure:

2n ₁ d ₁−(λ/2)=2k*(λ/2),k=1,2,3 . . . ;

2n ₁ d ₁+2n ₂ d ₂=2k′*(λ/2),k′=1,2,3 . . . ;

4n ₁ d ₁−3(λ/2)=2k″*(λ/2),k″=1,2,3 . . . .

For example, the incident light of first color has a wavelength in therange from 440 nm to 465 nm.

For example, both of the first optical film layer and the second opticalfilm layer have a refractive index in the range from 1.2 to 1.8.

For example, both of the first optical film layer and the second opticalfilm layer have a thickness in the range from 20 nm to 5000 nm.

For example, both of the first optical film layer and the second opticalfilm layer are made of at least one material selected from the groupconsisting of a siloxane added with a titanium oxide particle and anorganic resin added with a titanium oxide particle.

For example, the light conversion structure applied to a display devicefurther includes: a light conversion layer configured to transmit a partof the incident light of first color, and to allow another part of theincident light of first color light to exit as light of at least oneother color upon passing through the light conversion layer; awavelength of the incident light of first color is less than awavelength of light of the other color; the light filter structure is ona light-exiting side of the light conversion layer.

For example, the light conversion layer includes a quantum dot materialor a fluorescent material.

At least one embodiment of the present disclosure provides a backlightmodule, including a light source and a light conversion structureapplied to a display device according to any one of the aboveembodiments, the light conversion structure is located on alight-exiting side of the light source, light emitted from the lightsource is the incident light of first color.

For example, the light conversion layer includes a quantum dot material.

For example, the quantum dot material is a mixed quantum dot material,and the mixed quantum dot material includes a mixture of a quantum dotmaterial of second color and a quantum dot material of third color toallow the incident light of first color to exit as light of second colorand light of third color upon passing through the light conversionlayer.

For example, the backlight module further includes: a light adjustmentstructure on a side of the light conversion structure far away from thelight source to extract light uniformly.

At least one embodiment of the present disclosure provides a colorfilter substrate including the light conversion structure applied to adisplay device according to any one of the above embodiments, the lightconversion structure further includes a color filter layer located on alight incident side of the light filter structure, the color filterlayer includes a light conversion portion and a light transmissionportion, the light transmission portion is configured to directlytransmit the incident light of first color, the light conversion portionis configured to allow the incident light of first color to exit aslight of at least one other color upon passing through the lightconversion portion, a wavelength of the incident light of first color issmaller than a wavelength of the light of other color, and the lightconversion portion includes a quantum dot material.

For example, the quantum dot material includes a quantum dot material ofsecond color and a quantum dot material of third color to allow theincident light of first color to exit as light of second color and lightof third color upon passing through the light conversion portion.

For example, the light filter structure includes a hollowed-outstructure, and an orthographic projection of the hollowed-out structureon the color filter layer falls within an orthographic projection of thelight transmission portion on the color filter layer.

At least one embodiment of the present disclosure provides a displaydevice including the light conversion structure applied to a displaydevice according to any one of the above embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to clearly illustrate the technical solutions of theembodiments of the present disclosure, the drawings of the embodimentswill be briefly described in the following; it is obvious that thedescribed drawings are only related to some embodiments of the presentdisclosure without constituting any limitation thereto.

FIG. 1A is a schematic diagram illustrating a light filter structure anda working principle thereof in a light conversion structure according toan example of an embodiment of the present disclosure;

FIG. 1B is a schematic diagram illustrating a light filter structure anda working principle thereof in a light conversion structure according toanother example of an embodiment of the present disclosure;

FIG. 1C is a schematic diagram illustrating a light filter structure anda working principle thereof in a light conversion structure according toyet another example of an embodiment of the present disclosure;

FIG. 1D is a schematic diagram illustrating a light filter structure anda working principle thereof in a light conversion structure according tofurther another example of an embodiment of the present disclosure;

FIG. 1E is a schematic diagram illustrating a transmittance of whitelight at a light-exiting side of a light filter structure according toan embodiment of the present disclosure;

FIG. 2A is a partial structural diagram illustrating a display deviceincluding a light conversion structure according to an example of anembodiment of the present disclosure;

FIG. 2B is a partial structural diagram illustrating a light conversionstructure according to another example of an embodiment of the presentdisclosure;

FIG. 3 is a partial structural diagram illustrating a backlight moduleincluding a light conversion structure according to an embodiment of thepresent disclosure; and

FIG. 4 is a partial structural diagram illustrating a color filtersubstrate including a light conversion structure according to anembodiment of the present disclosure.

DETAILED DESCRIPTION

In order to make objects, technical details and advantages of theembodiments of the present disclosure apparent, the technical solutionsof the embodiments will be described in a clearly and fullyunderstandable way in connection with the drawings related to theembodiments of the present disclosure. Apparently, the describedembodiments are just a part but not all of the embodiments of thepresent disclosure. Based on the described embodiments herein, thoseskilled in the art can acquire other embodiment(s), without anyinventive work, which should be within the protection scope of thepresent disclosure.

Unless otherwise defined, all the technical and scientific terms usedherein have the same meanings as commonly understood by one of ordinaryskill in the art to which the present disclosure belongs. The terms“first,” “second,” etc., which are used in the present disclosure, arenot intended to indicate any sequence, amount or importance, butdistinguish various components. The terms “comprise,” “comprising,”“include,” “including,” etc., are intended to specify that the elementsor the objects stated before these terms encompass the elements or theobjects and equivalents thereof listed after these terms, but do notpreclude the other elements or objects. “On,” “under,” “right,” “left”and the like are only used to indicate relative position relationship,and when the position of the object which is described is changed, therelative position relationship may be changed accordingly.

In the study, the inventor(s) of the present application noticed theproblems existed in a display device using a quantum dot (QD) colorfilter that, the quantum material has a concentration limit which ishard to be increased, the efficiency of quantum conversion is poor, andit's unable to be matched with a color filter in thickness, and thelike.

Embodiments of the present disclosure provide a light conversionstructure applied to a display device, and a backlight module, a colorfilter substrate, and a display device including the light conversionstructure. A light conversion structure applied to a display deviceaccording to an embodiment of the present disclosure includes a lightfilter structure including a first optical film layer and a secondoptical film layer which are alternately arranged and attached to eachother, a total number of the first optical film layer and the secondoptical film layer is N, N is an even number; and a refractive index ofthe first optical film layer is greater than that of the second opticalfilm layer; one of a surface of the first optical film layer far awayfrom the second optical film layer and a surface of the second opticalfilm layer far away from the first optical film layer is a lightincident surface of the light filter structure, and the other one of thesurface of the first optical film layer far away from the second opticalfilm layer and the surface of the second optical film layer far awayfrom the first optical film layer is a light-exiting surface of thelight filter structure; a part of incident light of first color that isreflected by the light incident surface is a first reflected light, apart of the incident light of first color that is reflected by aninterface between the first optical film layer and the second opticalfilm layer is a second reflected light, and an optical path differencebetween the first reflected light and the second reflected light is aninteger multiple of a wavelength of the incident light of first color.The light conversion structure can reflect a part of the incident lightof first color to allow the incident light of first color to be reused,thereby improving a utilization of a light-emitting material in thedisplay device.

A light conversion structure applied to a display device, and abacklight module, a color filter substrate and a display deviceincluding the light conversion structure, provided by the embodiment ofthe present disclosure, will be described below with reference to theaccompanying drawings.

An embodiment of the present disclosure provides a light conversionstructure applied to a display device. FIG. 1A is a schematic diagramillustrating a light filter structure and a working principle thereof ina light conversion structure provided by an example of an embodiment ofthe present disclosure. As illustrated in FIG. 1A, the light filterstructure 100 includes a first optical film layer 110 and a secondoptical film layer 120 which are alternately arranged and attached toeach other, and a total number of the first optical film layer 110 andthe second optical film layer 120 is N. A refractive index n₁ of thefirst optical film layer 110 is greater than a refractive index n₂ ofthe second optical film layer 120. FIG. 1A is described with referenceto the case where the light filter structure 100 includes one pair offirst optical film layer and second optical film layer arranged in astacked manner, and mediums on both sides of the pair of first opticalfilm layer and second optical film layer in a Y direction each have arefractive index smaller than that of the first optical film layer 110and the second optical film layer 120, by way of example. One of asurface 111 of the first optical film layer 110 far away from the secondoptical film layer 120 and a surface 121 of the second optical filmlayer 120 far away from the first optical film layer 110 is an lightincident surface 1001 of the light filter structure 100, and the otherone is a light-exiting surface 1003 of the light structure 100. A partof incident light 101 of first color that is reflected by the lightincident surface 1001 is a first reflected light 102, and a part of theincident light 101 of first color that is reflected by an interface 1002between the first optical film layer 110 and second optical film layers120 is a second reflected light 103, and an optical path differencebetween the first reflected light 102 and the second reflected light 103is an integral multiple of a wavelength of the incident light 101 offirst color. The light filter structure provided by the embodiment ofthe present disclosure can partly reflect the incident light of firstcolor, and the first reflected light in the reflected light is inconstructive interference with the second reflected light in thereflected light so that a reflection of the incident light of firstcolor is improved.

The light-exiting surface herein refers to a surface where most of theincident light of first color exits from the light filter structure, andthe light-exiting surface and the light incident surface are twosurfaces arranged in parallel.

FIG. 1A is described with reference to the case where the surface 121 ofthe second optical film layer 120 far away from the first optical filmlayer 110 is served as the light incident surface 1001 of the lightfilter structure 100, the interface 1002 is an interface between thesecond optical film layer 120 and the first optical film layer 110 whenthe incident light 101 of first color is incident onto the first opticalfilm layer 110 from the second optical film layer 120, and the incidentlight 101 of first color is perpendicularly incident onto the lightincident surface 1001 (that is, the incident light 101 of first colorpropagates in the Y direction), by way of example. It should beexplained that a path of the reflected light is schematically shifted inFIG. 1A in order to clearly illustrate several paths of the reflectedlight of the incident light of first color. In fact, in the case wherethe incident light 101 of first color is perpendicularly incident ontothe light incident surface 1001, the reflected light propagates in adirection opposite to the Y direction, and the reflected light returnsalong a path of the incident light.

For example, as illustrated in FIG. 1A, upon being incident onto thelight incident surface 1001, the incident light 101 of first color istransmitted and reflected, respectively, and the part of the incidentlight 101 of first color that is reflected by the light incident surface1001 is the first reflected light 102. The part of the incident light101 of first color that is transmitted to the second optical film layer120 is transmitted and reflected, respectively, again, upon beingincident onto the interface 1002, and the part of the incident light 101of first color that is reflected by the interface 1002 for one time isthe second reflected light 1031 (hereinafter, “the second reflectedlight 1031” refers to the part of the incident light 101 of first colorthat is reflected by the interface 1002 for one time); while the part ofthe incident light 101 of first color that is transmitted to the firstoptical film layer 110 has a portion which would exit from thelight-exiting surface 1003, and has another portion which would bereflected by a side of the light-exiting surface 1003 facing theinterface 1002, that is, the third reflected light 104.

For example, a thickness of the second optical film layer 120 is d₂, anda wavelength of the incident light 101 of first color is λ, then anoptical path difference between the first reflected light 102 and thesecond reflected light 1031 satisfies a formula of 41=2n₂d₂. Because theoptical path difference between the first reflected light 102 and thesecond reflected light 1031 is an integral multiple of the wavelength ofthe incident light 101 of first color, that is, Δ1=2n₂d₂=2k*(λ/2), k=1,2, 3 . . . , the first reflected light 102 is in constructiveinterference with the second reflected light 1031, that is, a lightintensity obtained by the first reflected light 102 being ininterference with the second reflected light 1031 is a maximum value, sothat a reflection effect of the light filter structure to the incidentlight of first color is enhanced.

For example, as illustrated in FIG. 1A, an optical path differencebetween the first reflected light 102 and the third reflected light 104satisfies a formula of Δ2=2n₂d₂+2n₁d₁−(λ/2); because the refractiveindex of the first optical film layer 110 is greater than the refractiveindices of the mediums on both sides of the first optical film layer 110in the Y direction, an additional optical path difference caused by ahalf wave loss when the incident light 101 of first color is reflectedby the side of the light-exiting surface 1003 facing the interface 1002should also be taken into account. Because the optical path differencebetween the first reflected light 102 and the third reflected light 104is an integral multiple of the wavelength of the incident light 101 offirst color, that is, Δ2=2n₂d₂+2n₁d₁−(λ/2)=2k′*(λ/2), k′=1, 2, 3 . . . ,the first reflected light 102 is in constructive interference with thethird reflected light 104, that is, a light intensity obtained by thefirst reflected light 102 being in interference with the third reflectedlight 104 is a maximum value, so that a reflection effect provided bythe light filter structure to the incident light of first color isenhanced.

For example, as illustrated in FIG. 1A, a part of the incident light 101of first color that is reflected by the interface 1002 between the firstoptical film layer 110 and the second optical film layer 120 for twotimes is a second reflected light 1032 (hereinafter, the secondreflected light 1032 is also referred to as “the part of the incidentlight 101 of first color that is reflected by the interface 1002 betweenthe first optical film layer 110 and the second optical film layer 120for two times), and an optical path difference between the firstreflected light 102 and the second reflected light 1032 satisfies aformula of Δ3=4n₂d₂. Because the optical path difference between thefirst reflected light 102 and the second reflected light 1032 is anintegral multiple of the wavelength of the incident light 101 of firstcolor, that is, Δ3=4n₂d₂=2k″*(λ/2), k″=1, 2, 3, . . . , the firstreflected light 102 is in constructive interference with the secondreflected light 1032, that is, a light intensity obtained by the firstreflected light 102 being in constructive interference with the secondreflected light 1032 is a maximum value, so that a reflection effectprovided by the light filter structure to the incident light of firstcolor is enhanced.

Therefore, the incident light of first color, upon passing through thelight filter structure provided by this embodiment, generates both oftransmitted light and reflected light, and the transmitted light exitsfrom the light-exiting surface. The second reflected light obtained byreflecting the incident light of first color at the interface betweenthe first optical film layer and the second optical film layer, and/or,the third reflected light obtained by reflecting the incident light offirst color at the side of the light-exiting surface facing theinterface, is/are in constructive interference with the first reflectedlight obtained by reflecting the incident light of first color on thelight incident surface, so that a reflection effect provided by thelight filter structure to the incident light of first color is enhanced.In this way, a part of the incident light of first color that isreflected by the light filter structure can be reused, so as to improvea utilization of light-emitting material in the display device.

For example, FIG. 1B is a schematic diagram illustrating a light filterstructure and a working principle thereof in a light conversionstructure provided by another example of an embodiment of the presentdisclosure. As illustrated in FIG. 1B, FIG. 1B is described withreference to the case where the light filter structure 100 includes onepair of first optical film layer and second optical film layer which arearranged in a stacked manner, and refractive indices of mediums on bothsides of the pair of first optical film layer and second optical filmlayer in the Y direction are all smaller than the refractive indices ofthe first optical film layer 110 and the second optical film layer 120,by way of example. This example is described with reference to the casewhere the light incident surface 1001 is a surface 111 of the firstoptical film layer 110 far away from the second optical film layer 120,by way of example. According to the above analysis, the incident light101 of first color, upon being incident into the light filter structure100, satisfies formulas as follows:

2n ₁ d ₁−(λ/2)=2k*(λ/2),k=1,2,3 . . . ;

2n ₁ d ₁+2n ₂ d ₂=2k′*(λ/2),k′=1,2,3 . . . ;

4n ₁ d ₁−3(λ/2)=2k″*(λ/2),k″=1,2,3 . . . .

In the above formula derivation, an additional optical path differencecaused by a “half wave loss” when the incident light 101 of first coloris reflected by the interface 1002 between the first optical film layer110 and the second optical film layer 120 and is reflected by theinterface between the first optical film layer 110 and a medium on aside of the first optical film layer 110 far away from the secondoptical film layer 120.

For example, when the light filter structure includes a plurality ofpairs of first optical film layers and second optical film layers whichare arranged in a stacked manner, more formulas are included in theabove group of formulas of optical path difference.

For example, FIG. 1C is a schematic diagram illustrating a light filterstructure and a working principle thereof in a light conversionstructure according to yet another example of an embodiment of thepresent disclosure. As illustrated in FIG. 1C, FIG. 1C is described withreference to the case where the light filter structure 100 includes twopairs of first optical film layers and second optical film layers whichare arranged in a stacked manner, and the refractive indices of themediums surrounding the first optical film layer 110 and the secondoptical film layer 120, respectively, are smaller than the refractiveindices of the first optical film layer 110 and the second optical filmlayer 120, by way of example.

This example can be derived according to the principle that the incidentlight 101 of first color illustrated in FIG. 1A is reflected by thelight filter structure 100, which satisfies the following formulas:

2n ₂ d ₂=2k*(λ/2),k=1,2,3 . . . ;

2n ₂ d ₂+2n ₁ d ₁−(λ/2)=2k′*(λ/2),k′=1,2,3 . . . ;

4n ₂ d ₂=2k″*(λ/2),k″=1,2,3 . . . .

It should be explained that, the second formula in the above formulasrefers to an optical path difference between the second reflected lightobtained by reflecting the incident light 101 of first color at a secondinterface 1002 (i.e., the second interface in the Y direction) and thefirst reflected light being an integral multiple of the wavelength ofthe incident light of first color.

For example, what is different from FIG. 1A is that, this examplefurther includes the case where the incident light 101 of first color isreflected at a third interface 1002 (i.e., the third interface in the Ydirection), and in this case, an optical path difference between thesecond reflected light 1033 obtained by reflecting the incident light101 of first color at the third interface 1002 and the first reflectedlight 102 satisfies a formula of Δ4=3n₂d₂+3n₁d₁−(λ/2).

For example, this example further includes the case where the incidentlight 101 of first color is reflected at the side of the light-exitingsurface 1003 facing the third interface 1002, and in this case, anoptical path difference between the third reflected light 104 obtainedby reflecting the incident light 101 of first color and the firstreflected light 102 satisfies a formula of Δ5=4n₂d₂+4n₁d₁−(λ/2).

In this example, because the optical path difference between thereflected light (excluding the first reflected light) obtained byreflecting the incident light 101 of first color at the light filterstructure 100 and the first reflected light 102 is an integral multipleof the wavelength of the incident light 101 of first color, the opticalpath differences 44 and 45 also satisfy the following formulas:

3n ₂ d ₂+3n ₁ d ₁−(λ/2)=2k′″*(λ/2),k′″=1,2,3 . . . ;

4n ₂ d ₂+4n ₁ d ₁−(λ/2)=2k″″*(λ/2),k″″=1,2,3 . . . .

The above formulas are only several main formulas in the case where thelight filter structure includes only two pairs of first optical filmlayers and second optical film layers, and there may be other formulaswhich are not enumerated here but can be deduced based on the previousanalysis process.

In the case where the light filter structure includes more than twopairs of first optical film layers and second optical film layers, theformula that the incident light of first color satisfies can be derivedaccording to the above deducing process, without enumerated here.

For example, FIG. 1D is a schematic diagram illustrating a light filterstructure and a working principle thereof in a light conversionstructure according to further another example of an embodiment of thepresent disclosure. As illustrated in FIG. 1D, FIG. 1D is described withreference to the case where the light filter structure 100 includes twopairs of first optical film layers and second optical film layersarranged in a stacked manner, a surface of the first optical film layer110 far away from the second optical film layer 120 is the lightincident surface of the light filter structure 100, and refractiveindices of mediums surrounding the two pairs of first optical filmlayers and second optical film layers are all smaller than refractiveindices of the first optical film layer 110 and the second optical filmlayer, by way of example.

In this example, the optical path difference between the reflected light(excluding the first reflected light) and the first reflected light 102upon the incident light 101 of first color being reflected by the lightfilter structure 100 as illustrated in FIG. 1C is an integer multiple ofthe wavelength of the incident light 101 of first color, so the opticalpath differences satisfy the following formulas:

2n ₁ d ₁−(λ/2)=2k*(λ/2),k=1,2,3 . . . ;

2n ₁ d ₁+2n ₂ d ₂−(λ/2)=2k′*(λ/2),k′=1,2,3 . . . ;

4n ₁ d ₁−3(λ/2)=2k″*(λ/2),k″=1,2,3 . . . ;

3n ₂ d ₂+3n ₁ d ₁−(λ/2)=2k′″*(λ/2),k′″=1,2,3 . . . ;

4n ₂ d ₂+4n ₁ d ₁=2k″″*(λ/2),k″″=1,2,3 . . . .

The above formulas are only several main formulas in the case where thelight filter structure includes two pairs of first optical film layersand second optical film layers, and there may be other formulas whichare not enumerated here but can be deduced based on the previousanalysis process.

In the case where the light filter structure includes more than twopairs of first optical film layers and second optical film layers, theformulas that the incident light of first color satisfies can be derivedaccording to the above deducing process, without enumerated here.

For example, the incident light 101 of first color satisfying the aboveoptical path difference has a wavelength in the range from 440 nm to 465nm; that is, the incident light 101 of first color is blue light, whichare included but not limited in this embodiment.

For example, the refractive index n1 of the first optical film layer 110satisfying the above optical path difference is in the range from 1.2 to1.8, the refractive index n1 of the second optical film layer 120 is inthe range from 1.2 to 1.8, which are included but not limited in thisembodiment.

For example, the first optical film layer 110 and the second opticalfilm layer 120 may be composed of siloxane, organic resin or the likewhich is added with a metal oxide such as TiO₂ particle or added with anorganic particle, and a diameter of the particle is between 10 nm and 50nm, which are included but not limited in this embodiment.

For example, both of the first optical film layer 110 and the secondoptical film layer 120 satisfying the above optical path difference havea thickness in the range from 20 nm to 5000 nm.

For example, the thickness of each of the first optical film layer 110and the second optical film layer 120 may be in the range from 145 nm to363 nm.

For example, FIG. 1E is a schematic diagram illustrating a transmittanceof white light on a light-exiting side of a light filter structureprovided by an embodiment of the present disclosure. As illustrated inFIG. 1E, a solid line refers to a transmittance of the incident light offirst color at the light filter structure in the case where the lightfilter structure includes one pair of first optical film layer andsecond optical film layer, and a broken line refers to a transmittanceof the incident light of first color at the light filter structure inthe case where the light filter structure includes a plurality of pairsof first optical film layers and second optical film layers. As can beseen from FIG. 1E, when white light is incident into the light filterstructure, a transmittance of the incident light of first color (i.e.,the blue light waveband) is lower than that of the light in otherwavebands; that is, the light filter structure can enhance a reflectioneffect of the incident light of first color.

For example, as illustrated in FIG. 1E, compared with a light filterstructure including only one pair of first optical film layer and secondoptical film layer, a light filter structure including a plurality ofpairs of first optical film layers and second optical film layers allowsfor a lower transmittance of the incident light of first color; that is,the light filter structure including the plurality of pairs of firstoptical film layers and second optical film layers provides a betterreflection effect for the incident light of first color than the lightfilter structure including only one pair of first optical film layer andsecond optical film layer.

For example, FIG. 2A is a partial structural diagram illustrating adisplay device including a light conversion structure provided by anexample of an embodiment of the present disclosure. As illustrated inFIG. 2A, the light conversion structure applied to a display devicefurther includes a light conversion layer 200, and the light filterstructure 100 is located at a light-exiting side of the light conversionlayer 200; that is, the light exits from the light conversion layer 200enters the light filter structure 100. This embodiment is described withreference to the case where the light conversion structure is a partialstructure of a color filter substrate, by way of example. The lightconversion layer 200 is configured to transmit a part of the incidentlight 101 of first color, and to allow another part of the incidentlight 101 of first color to pass through the light conversion layer 200and exit as light of at least one other color; a wavelength of theincident light 101 of first color is smaller than a wavelength of thelight of the other colors.

For example, a part of the incident light 101 of first color passesthrough the light conversion layer 200 and then exits as light 201 ofsecond color and light 301 of third color.

For example, a material of the light conversion layer 200 includes aquantum dot material or a fluorescent material. Upon the incident light101 of first color being incident onto the light conversion layer 200,the material of the light conversion layer 200 is excited by theincident light 101 of first color to emit light of other colors, forexample, to emit light 201 of second color and light 301 of third color.

For example, the light 201 of second color that exits from the lightconversion layer 200 further contains a part of the incident light 101of first color which is mixed therein, and this part of the incidentlight 101 of first color may be reflected back into the light conversionlayer 200 by the light filter structure 100 to continue to excite thematerial of the light conversion layer 200 to emit the light 201 ofsecond color and the light 301 of third color. Therefore, the lightfilter structure provided by this embodiment can partly reflect theincident light of first color back into the light conversion layer, sothat the incident light of first color passes through the material ofthe light conversion layer for multiple times to improve the utilizationefficiency of the light-emitting material in the light conversion layerand reduce a usage amount of, for example, the quantum dot material(e.g., achieving a lower concentration, or matching with a lightconversion layer having smaller thickness), thereby overcoming theproblem of concentration limit of the quantum dot material. At the sametime, with the same color gamut, a cost of the quantum dot material andan environmental pollution can be reduced. In addition, in the casewhere the incident light of first color is blue light, the lightextraction rate of the blue light in the display device may also bereduced in this embodiment, thereby improving a visual experience of auser.

For example, in the manufacturing process, a first refractive indexmatching material layer (first optical film layer) with a predeterminedthickness may be manufactured on a substrate by using a spin coatingprocess, and the first refractive index matching material layer issubjected to a pre-baking process (70° C. to 150° C., 1 to 30 minutes)to be initially fixed. Then, a second refractive index matching materiallayer (second optical film layer) is manufactured on a side of the firstrefractive index matching material layer far away from the substrate byusing a spin coating process, and the second refractive index matchingmaterial layer is subjected to a pre-baking process and a post-bakingprocess (70° C. to 250° C., 1 to 30 minutes), sequentially, to beshaped. The control of values of the refractive index and the thicknessof the first optical film layer and the second optical film layerfollows the value range given by the above examples. Moreover, the lightfilter structure can also include one or more pair of first optical filmlayer and second optical film layer according to different requirements,without limited in this embodiment. For example, the light filterstructure can include two, three or more pairs of first optical filmlayers and second optical film layers.

For example, as illustrated in FIG. 2A, the display device provided bythis example further includes a backlight module 300, a first polarizer510, a first substrate 501, a second polarizer 520, a second substrate502, and a liquid crystal layer 600. This example is described withreference to the case where the display device is a liquid crystaldisplay device, by way of example, without limited thereto, and may alsobe, for example, an electroluminescence display device or the like.

For example, as illustrated in FIG. 2A, upon the part of the incidentlight 101 of first color that is transmitted being reflected by thelight filter structure 100, the reflected light is returned to theliquid crystal layer 600 and/or the backlight module 300; the reflectedlight may change its propagation direction in the liquid crystal layer600 and/or backlight module 300, and is incident onto the lightconversion layer 200, again, thereby further improving the utilizationof the incident light of first color.

For example, the incident light 101 of first color may be blue light,the light 201 of second color may be green light, and the light 301 ofthird color may be red light, which are included but not limited in thisembodiment. For example, the light of second color and the light ofthird color may be interchanged in this embodiment.

For example, FIG. 2B is a partial structural diagram illustrating alight conversion structure provided by another example of an embodimentof the present disclosure. As illustrated in FIG. 2B, the light filterstructure 100 in this example includes two pairs of first optical filmlayers and second optical film layers, which is included but not limitedin this example. For example, the light filter structure 100 may furtherinclude three or more pairs of first optical film layers and secondoptical film layers.

Another embodiment of the present disclosure provides a backlightmodule. FIG. 3 is a partial structural diagram illustrating a backlightmodule including a light conversion structure provided by an embodimentof the present disclosure. The backlight module provided by thisembodiment includes the light filter structure provided by any of theabove embodiments. As illustrated in FIG. 3, the backlight module 300includes: a light source 310, a light conversion structure applied to adisplay device and located on a light-exiting side of the light source310, and a light adjustment structure 320. The light adjustmentstructure 320 is located on a light-exiting side of the light conversionstructure to extract light uniformly. The light emitted from the lightsource 310 is the incident light 101 of first color.

This embodiment is described with reference to the case where thebacklight module 300 is an edge-type backlight module, by way ofexample. However, the embodiment is not limited thereto. For example,the backlight module may also be a direct-lit type backlight module.

For example, as illustrated in FIG. 3, the backlight module 300 furtherincludes a light guide plate 340 and a reflective layer 330 located at aside of the light guide plate 340 far away from the light conversionlayer 200.

In this embodiment, the light-exiting side of the light source 310refers to a light-exiting side of the light guide plate 340, theincident light 101 of first color that is emitted from the light source310 enters the light guide plate 340 and then exits through thelight-exiting side of the light guide plate 340.

For example, as illustrated in FIG. 3, the light adjustment structure320 may include a diffusion layer (not illustrated) configured todiffuse light, a prism layer (not illustrated) configured to gatherlight, and other film layers, without limited in this embodiment.

For example, as illustrated in FIG. 3, the light conversion structurefurther includes a light conversion layer 200 located between the lightfilter structure 100 and the light source 310. The light conversionlayer 200 is configured to transmit a part of the incident light 101 offirst color, and to allow another part of the incident light 101 offirst color to pass through the light conversion layer 200 and then exitas light of at least one other color; and the wavelength of the incidentlight 101 of first color is smaller than a wavelength of light of othercolors.

For example, the light conversion layer includes a quantum dot materialor a fluorescent material.

For example, as illustrated in FIG. 3, light of other colors includes atleast one of light 201 of second color and light 301 of third color; andthe light conversion layer 200 includes at least one of a quantum dotmaterial of second color and a quantum dot material of third color sothat the incident light 101 of first color can exit as at least one ofthe light 201 of second color and the light 301 of third color uponpassing through the light conversion layer 200.

For example, the quantum dot material is a mixed quantum dot material,and the mixed quantum dot material includes a mixture of a quantum dotmaterial of second color and a quantum dot material of third color sothat the incident light 101 of first color can exit as light 201 ofsecond color and light 301 of third color upon passing through the lightconversion layer 200.

This embodiment is described with reference to the case where thequantum dot material of second color and the quantum dot material ofthird color are a red quantum dot material and a green quantum dotmaterial, respectively, the entire light conversion layer is a quantumdot layer, the quantum dot layer is a mixture of red quantum dotmaterial and green quantum dot material, and the incident light of firstcolor is blue light, by way of example. A part of the blue incidentlight passes through a gap between quantum dots to exit as blue lightthrough the light conversion layer, and another part of the blueincident light excites the quantum dot material to emit red light andgreen light.

This embodiment is not limited thereto. For example, the incident lightof first color may also be blue light, and the light of other colorsincludes only yellow light; that is, the incident light of first colorexcites the quantum dot material to emit yellow light, and the bluelight and the yellow light are mixed to form white light.

Because the light 201 of second color and the light 301 of third colorcontain a part of the incident light 101 of first color mixed therein,respectively, the incident light 101 of first color is partly returnedto the quantum dot material of the light conversion layer to be utilizedfor several times upon the light 201 of second color and the light 301of third color containing a part of the incident light 101 of firstcolor mixed therein respectively passing through the light filterstructure 100, so that the usage amount of, for example, the quantum dotmaterial (for example, achieving a lower concentration, or matching witha light conversion layer having smaller thickness) is reduced, therebyovercoming the problem of concentration limit of the quantum dotmaterial. At the same time, with the same color gamut, the cost ofquantum dot material and the environmental pollution can be reduced.

Compared with a conventional backlight module, the backlight moduleusing the light conversion structure provided by the embodiment produceswhite light of wide color gamut, because the white light is generated byexciting, for example, the quantum dot material in the light conversionlayer.

Another embodiment of the present disclosure provides a color filtersubstrate. FIG. 4 is a partial structural diagram illustrating a colorfilter substrate including a light conversion structure provided by anembodiment of the present disclosure. This embodiment includes the lightfilter structure provided by any of the above embodiments. Asillustrated in FIG. 4, the color filter substrate 400 provided by thisembodiment includes a base substrate 410 and a light conversionstructure located on the base substrate 410. The light conversionstructure further includes a color filter layer 200 located at a lightincident side of the light filter structure 100; the color filter layer200 includes a light conversion portion 210 and a light transmissionportion 220. The light transmission portion 220 is configured todirectly transmit the incident light 101 of first color. The lightconversion portion 210 is configured to emit light of at least one othercolor upon the incident light 212 of first color passing through thelight conversion portion 210. The wavelength of the incident light 101of first color is smaller than a wavelength of light of the othercolors. Here, “directly transmit” refers to that the incident light 101of first color exits the light transmission portion 220 still as lightof first color.

In this embodiment, light of different colors emitted from the colorfilter layer 200 corresponds to sub-pixels of different colors,respectively; that is, the light transmission portion 220 and the lightconversion portion 210 correspond to sub-pixels of different colors,respectively.

For example, the light conversion portion includes a quantum dotmaterial or a fluorescent material.

For example, as illustrated in FIG. 4, the light conversion portion 210includes a first light conversion portion 211 and a second lightconversion portion 212. The first light conversion portion 211 isconfigured to allow the incident light 101 of first color to exit aslight 201 of second color upon passing through the first lightconversion portion 211. The second light conversion portion 212 isconfigured to allow the incident light 101 of first color to exit aslight 301 of third color upon passing through the second lightconversion portion 212. That is, the quantum dot material includes aquantum dot material of second color and a quantum dot material of thirdcolor, so as to allow the incident light 101 of first color to exit asthe light 201 of second color and the light 301 of third color,respectively, upon passing through the light conversion portion 210,respectively.

For example, as illustrated in FIG. 4, the light filter structure 100includes a hollowed-out structure 130, and an orthographic projection ofthe hollowed-out structure 130 on the color filter layer 200 fallswithin an orthographic projection of the light transmission portion 220on the color filter layer 200. For example, the hollowed-out structure130 can be manufactured by using a mask process.

For example, as illustrated in FIG. 4, the light filter structure 100may be located between the base substrate 410 and the color filter layer200. In this case, the incident light 101 of first color passes throughthe color filter layer 200, the light filter structure 100, and the basesubstrate 410 in sequence, which is included but not limited in thisembodiment. For example, the color filter layer may also be locatedbetween the light filter structure and the base substrate, and theincident light of first color passes through the base substrate, thecolor filter layer, and the light filter structure in sequence.

For example, as illustrated in FIG. 4, the incident light 101 of firstcolor passes through the light transmission portion 220 of the colorfilter layer 200 and then is incident into the light filter structure100. The light filter structure 100 transmits a part of the incidentlight 101 of first color and reflects another part of the incident light101 of first color, so that an extraction intensity of the incidentlight 101 of first color can be reduced as much as possible. Inaddition, a part of the incident light 101 of first color that isreflected may be returned to the liquid crystal layer and/or thebacklight module of the display device; this part of the incident light101 of first color may change its propagation direction in the liquidcrystal layer and/or the backlight module, and is incident into thecolor filter layer 200 again, thereby improving the utilization ratio ofthe incident light of first color.

For example, as illustrated in FIG. 4, the incident light 101 of firstcolor passes through the first light conversion portion 211 and thenexits as the light 201 of second color; and the incident light 101 offirst color passes through the second light conversion portion 212 andthen exits as the light 301 of third color. The light 201 of secondcolor and the light 301 of third color that exit from the color filterlayer 200 further contain a part of the incident light 101 of firstcolor mixed therein, respectively; and this part of the incident light101 of first color has a portion which is reflected back to the lightconversion portion 210 by the light filter structure 100, so as tocontinue to excite the material of the light conversion portion 210 toemit light 201 of second color and light 301 of third color. In thisway, the light filter structure provided by this embodiment can reflecta part of the incident light of first color back to the color filterlayer, so that the incident light of first color passes through amaterial of the light conversion portion for multiple times to improvethe utilization efficiency of the light-emitting material in the lightconversion portion and reduce the usage amount of, for example, thequantum dot material (e.g., achieving a lower concentration, or matchingwith a light conversion layer having smaller thickness), therebyovercoming the problem of concentration limit of the quantum dotmaterial. At the same time, with the same color gamut, the cost ofquantum dot material and the environmental pollution can be reduced.

For example, the light filter structure 100 can be manufactured toinclude one or more pair of first optical film layer and second opticalfilm layer according to different requirements, which is not limited inthis embodiment.

For example, the light filter structure can include two, three or morepairs of first optical film layers and second optical film layers.

Another embodiment of the present disclosure provides a display device,which includes the light conversion structure provided by any of theabove embodiments. The display device can partly reflect the incidentlight of first color back to the light conversion layer, so that theincident light of first color passes through a material in the lightconversion layer for multiple times to improve the utilizationefficiency of the light-emitting material in the light conversion layerand to reduce the usage amount of, for example, the quantum dot material(e.g., achieving a lower concentration, or matching with an opticalconversion layer having smaller thickness), thereby overcoming theproblem of concentration limit of the quantum dot material. At the sametime, with the same color gamut, the cost of quantum dot material andthe environmental pollution can be reduced.

For example, the display device may be a display device such as a liquidcrystal display device, an organic light-emitting diode (OLED) displaydevice, and a product or a component having a display function such as atelevision, a digital camera, a mobile phone, a watch, a tabletcomputer, a notebook computer, and a navigation device. This embodimentis not limited thereto.

The following statements should be noted:

(1) Unless otherwise defined, the same reference numeral refers to thesame meaning in the embodiments and the accompanying drawings of thepresent disclosure.

(2) The accompanying drawings involve only the structure(s) inconnection with the embodiment(s) of the present disclosure, and otherstructure(s) can be referred to common design(s).

(3) For the purpose of clarity only, in accompanying drawings forillustrating the embodiment(s) of the present disclosure, a layer or anarea may be enlarged. It should be understood that, in the case in whicha component such as a layer, film, area, substrate or the like isreferred to be “on” or “under” another component, it may be directly onor under the another component or a component is interposedtherebetween.

The above are only specific implementations of the present disclosure,and the protection scope of the present disclosure is not limitedthereto. Any changes or substitutions easily occur to those skilled inthe art within the technical scope of the present disclosure should becovered in the protection scope of the present disclosure. Therefore,the protection scope of the present disclosure should be based on theprotection scope of the claims.

1. A light conversion structure applied to a display device, comprising:a light filter structure comprising a first optical film layer and asecond optical film layer which are alternately arranged and attached toeach other, a total number of the first optical film layer and thesecond optical film layer being N, wherein N is an even number, and arefractive index of the first optical film layer is greater than that ofthe second optical film layer, one of a surface of the first opticalfilm layer far away from the second optical film layer and a surface ofthe second optical film layer far away from the first optical film layeris a light incident surface of the light filter structure, and the otherone of the surface of the first optical film layer far away from thesecond optical film layer and the surface of the second optical filmlayer far away from the first optical film layer is a light-exitingsurface of the light filter structure, wherein a part of an incidentlight of first color that is reflected by the light incident surface isa first reflected light, a part of the incident light of first colorthat is reflected by an interface between the first optical film layerand the second optical film layer is a second reflected light, and anoptical path difference between the first reflected light and the secondreflected light is an integer multiple of a wavelength of the incidentlight of first color.
 2. The light conversion structure applied to adisplay device according to claim 1, wherein a part of the incidentlight of first color that is reflected by a side of the light-exitingsurface facing the interface is a third reflected light, and an opticalpath difference between the first reflected light and the thirdreflected light is an integer multiple of the wavelength of the incidentlight of first color.
 3. The light conversion structure applied to adisplay device according to claim 2, wherein the light filter structurecomprises one pair of first optical film layer and second optical filmlayer, the light incident surface is a surface of the second opticalfilm layer far away from the first optical film layer, the first opticalfilm layer has a refractive index of n1 and a thickness of d1, and thesecond optical film layer has a refractive index of n2 and a thicknessof d2, the incident light of first color has a wavelength of λ, and theincident light of first color satisfies the following formulas uponbeing incident into the light filter structure:2n ₂ d ₂=2k*(λ/2),k=1,2,3 . . . ;2n ₂ d ₂+2n ₁ d ₁−(λ/2)=2k′*(λ/2),k′=1,2,3 . . . ;4n ₂ d ₂=2k″*(λ/2),k″=1,2,3 . . . .
 4. The light conversion structureapplied to a display device according to claim 2, wherein the lightfilter structure comprises one pair of first optical film layer andsecond optical film layer, the light incident surface is a surface ofthe first optical film layer far away from the second optical filmlayer, the first optical film layer has a refractive index of n₁ and athickness of d₁, and the second optical film layer has a refractiveindex of n₂ and a thickness of d₂, the incident light of first color hasa wavelength of λ, and the incident light of first color satisfies thefollowing formulas upon being incident into the light filter structure:2n ₁ d ₁−(λ/2)=2k*(λ/2),k=1,2,3 . . . ;2n ₁ d ₁+2n ₂ d ₂=2k′*(λ/2),k′=1,2,3 . . . ;4n ₁ d ₁−3(λ/2)=2k″*(λ/2),k″=1,2,3 . . . .
 5. The light conversionstructure applied to a display device according to claim 1, wherein theincident light of first color has a wavelength in the range from 440 nmto 465 nm.
 6. The light conversion structure applied to a display deviceaccording to claim 1, wherein both of the first optical film layer andthe second optical film layer have a refractive index in the range from1.2 to 1.8.
 7. The light conversion structure applied to a displaydevice according to claim 1, wherein both of the first optical filmlayer and the second optical film layer have a thickness in the rangefrom 20 nm to 5000 nm.
 8. The light conversion structure applied to adisplay device according to claim 1, wherein both of the first opticalfilm layer and the second optical film layer are made of at least onematerial selected from the group consisting of a siloxane added with atitanium oxide particle and an organic resin added with a titanium oxideparticle.
 9. The light conversion structure applied to a display deviceaccording to claim 1, further comprising: a light conversion layerconfigured to transmit a part of the incident light of first color, andto allow another part of the incident light of first color light to exitas light of at least one other color upon passing through the lightconversion layer, a wavelength of the incident light of first colorbeing less than a wavelength of light of the other color, wherein thelight filter structure is on a light-exiting side of the lightconversion layer.
 10. The light conversion structure applied to adisplay device according to claim 9, wherein the light conversion layercomprises a quantum dot material or a fluorescent material.
 11. Abacklight module comprising: a light source; a light conversionstructure applied to a display device according to claim 9, the lightconversion structure being located on a light-exiting side of the lightsource, wherein light emitted from the light source is the incidentlight of first color.
 12. The backlight module according to claim 11,wherein the light conversion layer comprises a quantum dot material. 13.The backlight module according to claim 12, wherein the quantum dotmaterial is a mixed quantum dot material, the mixed quantum dot materialcomprising a mixture of a quantum dot material of second color and aquantum dot material of third color to allow the incident light of firstcolor to exit as light of second color and light of third color uponpassing through the light conversion layer.
 14. The backlight moduleaccording to claim 11, further comprising: a light adjustment structureon a side of the light conversion structure far away from the lightsource to extract light uniformly.
 15. A color filter substratecomprising the light conversion structure applied to a display deviceaccording to claim 1, wherein the light conversion structure furthercomprises a color filter layer located on a light incident side of thelight filter structure, the color filter layer comprises a lightconversion portion and a light transmission portion, the lighttransmission portion is configured to directly transmit the incidentlight of first color, the light conversion portion is configured toallow the incident light of first color to exit as light of at least oneother color upon passing through the light conversion portion, awavelength of the incident light of first color is smaller than awavelength of the light of other color, and the light conversion portioncomprises a quantum dot material.
 16. The color filter substrateaccording to claim 15, wherein the quantum dot material comprises aquantum dot material of second color and a quantum dot material of thirdcolor to allow the incident light of first color to exit as light ofsecond color and light of third color upon passing through the lightconversion portion.
 17. The color filter substrate according to claim15, wherein the light filter structure comprises a hollowed-outstructure, and an orthographic projection of the hollowed-out structureon the color filter layer falls within an orthographic projection of thelight transmission portion on the color filter layer.
 18. A displaydevice comprising the light conversion structure applied to a displaydevice according to claim
 1. 19. The light conversion structure appliedto a display device according to claim 2, further comprising: a lightconversion layer configured to transmit a part of the incident light offirst color, and to allow another part of the incident light of firstcolor light to exit as light of at least one other color upon passingthrough the light conversion layer, a wavelength of the incident lightof first color being less than a wavelength of light of the other color,wherein the light filter structure is on a light-exiting side of thelight conversion layer.
 20. The light conversion structure applied to adisplay device according to claim 3, further comprising: a lightconversion layer configured to transmit a part of the incident light offirst color, and to allow another part of the incident light of firstcolor light to exit as light of at least one other color upon passingthrough the light conversion layer, a wavelength of the incident lightof first color being less than a wavelength of light of the other color,wherein the light filter structure is on a light-exiting side of thelight conversion layer.